This invention relates generally to the use of bronchoscopes and other devices to gain access to the interior of a lung or to the mediastinal space around the lung. In particular, the invention relates to auxiliary access devices and tools for use with conventional bronchoscopes or other endoscopes to enable the delivery of more and larger devices to a target site than is currently possible through a typical endoscope or bronchoscope.
Most bronchoscopy cases use the bronchoscope simply as a tool to access the bronchi (transnasal, oral or trachea access to the lung) and possibly visualize abnormal colors from adjacent pathologic tissue. Most bronchoscope-based biopsies target tissues that lie outside the bronchi trunk; thus, the interventionalist needs external image guidance to place the tip of a biopsy system and confirm the direction of delivery to be sure to traverse the target. Flexible scopes are limited in depth of access since they are large (5 mm diameter) and not extremely flexible. They have a working channel of only 2.0 mm so the user is limited in the choice of devices that can be passed through. However, they are steerable, can be locked in place and are substantially stiff to support devices that are prone to buckling (such as compression of a spring needle to traverse a lesion).
One type of conventional flexible bronchoscope is described in U.S. Pat. No. 4,880,015, the disclosure of which is incorporated herein by reference. As shown in FIGS. 1-4, bronchoscope 10 measures 790 mm in length and has two main parts, a working head 14 and an insertion tube 11. The working head contains an eyepiece 15; an ocular lens with a diopter adjusting ring 25; attachments for the suction tubing 24 and a suction valve 21 and for the cold halogen light source 16 and 18; and an access port or biopsy inlet 19, through which various devices and fluids can be passed into the working channel 29 and out the distal end of the bronchoscope. The working head is attached to the insertion tube, which typically measures 580 mm in length and 6.3 mm in diameter. The insertion tube contains fiberoptic bundles (which terminate in the objective lens 30 at the distal tip 12), two light guides 31 and the working channel 29.
The distal end of the bronchoscope has the ability to bend anterior and posterior only, with the exact angle of deflection depending on the instrument used. A common range of bending is from 160 degrees forward to 90 degrees backward, for a total of 250 degrees, as shown at element 13 in FIGS. 3A and 3B. Bending is controlled by the operator by adjusting an angle lock lever 22 and angulation lever 23 on the working head.
Pulmonologists use such bronchoscopes to inspect the interior of the lungs and to perform a variety of procedures. Devices, such as biopsy forceps and brushes, can be passed through the length of the bronchoscope via the working channel into a patient's lungs to obtain tissue samples. For example, a biopsy needle such as that described in U.S. Pat. No. 4,766,906 (the disclosure of which patent is incorporated herein by reference) may be inserted into a patient's lung via the working channel of a flexible bronchoscope. Once the needle is in place at the distal end of the bronchoscope, the pulmonologist can use the needle to, e.g., biopsy a lymph node in the mediastinal space adjacent the bronchus in which the bronchoscope is placed. As described in the '906 patent, the pulmonologist makes a stabbing motion with the bronchoscope and needle to penetrate the bronchial wall and the lymph node. Other examples of biopsy needles used via the working channel of bronchoscopes may be found in U.S. Pat. No. 5,056,529, U.S. Pat. No. 4,532,935 and U.S. Pat. No. 4,702,260, the disclosures of which are incorporated herein by reference.